141.

If one wishes to design a microarray chip for whole-genome expression analysis of a eukaryotic system, which region of the gene should be preferred for selection of unique target sequences?

• any region of the coding DNA sequence (CD)

• 3' region of the CDS and 3' untranslated region (UTR)

• 5' region of the CDS and 5' UTR

• 1^st intron only

For 5' end labeling of DNA, the following reactions are carried out sequentially as indicated.

5'-dephosphorylated DNA + [γ³²P] dATP + T₄-polynucelotide kinase (T4PNK) and incubated for 2 hours → ammonium acetate →tris-EDTA → ethanol

If trace amount of NH₄⁺ is present in the initial DNA mix, which of the following statements would most likely be true?

• NH₄⁺ ion activates T4PNK, thereby increasing the labeling efficiency.

• NH₄⁺ ion inhibits T4PNK, therefore should not be present in the DNA mix.

• NH₄⁺ ion does not have any effect on T4PNK.

• NH₄⁺ ion dephosphorylates DNA, thereby increasing the labeling efficiency.

Four different receptors viz, A, B, C, and D bond to the same ligand X. In order to determine which receptor has the highest binding affinity following experiment was carried out. Cells were transfected with green fluorescence protein (GFP)-tagged receptors (A, B, C, and D) individually, then incubated with red fluorescence (RFP)-tagged -'X' and subjected to FACS analysis. Following are the results

Which receptor has the highest ligand binding affinity?

• A

• B

• C

• D

During line transect sampling of two solitary species of ground mammals the following observation was made:

		Smaller species	Larger species
A	Transect length	100 km	100 km
B	No. of animals sighted	30	36
C	Mean perpendicular distance from transect line	10 m	40 m

Which of the following can be inferred from the data?

• The smaller species is ore abundant but seen less frequently.

• The smaller species are less abundant and seen less frequently.

• The larger species are more abundant but seen less frequently.

• The larger species are seen more frequently, but its abundance cannot be compared with the smaller species.

A protein contains 2 Trp and 4 Tyr residues. The molecular mass of the protein is 17000 D and that of Trp and try ae 204 and 180 D respectively. Values of E, the absorption coefficient of 1% (g/ v) solutions of Trp and Tyr in a 1-cm cell at 280 nm, are 269.60 and 8.33 respectively. The absorption of 1 mg/ ml protein solution in 1-cm cell at 280 nm will be:

• 0.1

• 1.0

• 0.7

• 1.7